bug#43148: 27.1; Widget text seems to disappear when building with Cairo and Xaw

[tastytea via "Bug reports for GNU Emacs, the Swiss army knife of text editors" <bug-gnu-emacs@gnu.org>]

On 2020-11-28 17:22+0900 YAMAMOTO Mitsuharu
<mituharu@math.s.chiba-u.ac.jp> wrote:

> On Wed, 25 Nov 2020 11:30:07 +0900,
> Basil L. Contovounesios wrote:
> > 
> > Robert Pluim <rpluim@gmail.com> writes:
> >   
> > >>>>>> On Tue, 01 Sep 2020 17:09:18 +0300, Eli Zaretskii
> > >>>>>> <eliz@gnu.org> said:  
> > >  
> > >     >> From: Pouar Dragon <pouar@pouar.net>
> > >     >> Date: Mon, 31 Aug 2020 21:34:46 -0500
> > >     >> 
> > >     >> widgets when building with Xaw and Cairo seem to have
> > >     >> missing text, looking like this
> > >     >> 
> > >     >> problem seems to go away when
> > >     >> 5f4e8e2e088de9fb76cb631077c6eddd3219f594 is reverted  
> > >  
> > >     Eli> Thanks.  I hope Yamamoto-san will be able to take a look
> > >     Eli> at this.  
> > >
> > > Putting on my 'let's simplify' hat, is this really a combination
> > > we want to spend time on? Lucid + Xaw + Cairo is decidedly
> > > non-mainstream (Iʼm surprised it even builds).  
> > 
> > FWIW, I've been happily using Lucid + Xaw3D for several years, and
> > Cairo ever since it became stable in Emacs 27 and the default
> > configuration in Emacs 28.
> > 
> > I usually have menu-bar-mode off, but like other reports in this
> > thread, the menus look fine when I do open them, e.g. after 'emacs
> > -Q'.
> > 
> > Could the issue depend on e.g. the version of Cairo?  (I seem to
> > have an older version than the OP.)  
> 
> Possibly.  The OP seems to use cairo 1.17.3, which is not a release
> version (the latest is 1.16.0) and even not the snapshot one (the
> latest is 1.17.2 according to https://cairographics.org).

I experience the same issue as the OP with lucid and cairo 1.16.0,
with and without xaw3d, on Gentoo Linux. The problem goes away if I
disable cairo.
The same happens with 28.0.50, commit
1a3aa6043a51e5bb4007889dd7dcabb55dc44132.

Configured using: 
./configure […] --without-compress-install --without-hesiod
--without-pop --with-dumping=pdumper --with-file-notification=inotify
--enable-acl --with-dbus --with-modules --without-gameuser
--with-libgmp --with-gpm --with-json --without-kerberos
--without-kerberos5 --with-lcms2 --with-xml2 --without-mailutils
--without-selinux --with-gnutls --without-libsystemd --with-threads
--without-wide-int --with-zlib --with-sound=no --with-x --without-ns
--without-gconf --without-gsettings --without-toolkit-scroll-bars
--with-gif --with-jpeg --with-png --with-rsvg --with-tiff --with-xpm
--without-imagemagick --with-xft --with-cairo --with-harfbuzz
--without-libotf --without-m17n-flt --with-x-toolkit=lucid --with-xaw3d

cairo is configured using: 
./configure […] --with-x --enable-tee --enable-xlib
--enable-xlib-xrender --enable-xcb --enable-xcb-shm --disable-quartz
--disable-quartz-image --disable-test-surfaces --disable-glesv2
--enable-gobject --enable-gl --disable-static --enable-svg
--disable-trace --disable-valgrind --enable-ft --enable-interpreter
--enable-pdf --enable-png --enable-ps --enable-script --disable-drm
--disable-directfb --disable-gallium --disable-qt --disable-vg
--disable-xlib-xcb